remove alt-- shortcut

replace with ctrl-shift--

alt is not safe for defaults
use box-flex to layout quickhelp
widen modal dialogs on wide displays

needed for quick help layout with multiple meta keys
Merge pull request #5368 from jdfreder/specifity

Flexbox classes specificity fixes
Merge pull request #5375 from minrk/remove-mathjax-hack

remove unnecessary (?) onload hack from mathjax macro
better log message in deprecated files/ redirect
only check listdir on dirs

is_hidden is called with files, not just dirs
Merge pull request #5326 from takluyver/iptest-gardening

Some gardening on iptest result reporting
Merge pull request #5390 from minrk/finish-5333

finish PR #5333
Merge pull request #5389 from minrk/log-files-redirect

better log message in deprecated files/ redirect
Merge pull request #5403 from minrk/alt-shortcut-bad

remove alt-- shortcut
Don't use fork to start the notebook in js tests

It can encounter a weird segfault on OS X with sqlite when Qt is present (?!)

The main reason to use the fork was to get the port number,
but this is easy now that notebooks write a server-info file.

Further advantage is that the symptom of a failed server start
is no longer silence and hanging tests, but an actual failure with the server's log output.
html and js tests require sqlite3 (session manager)
don't launch js tests if the server didn't start
Merge branch 'master' of github.com:ipython/ipython
Prevent tab key from bubbling when the completer is open
Add dual mode JS tests
s/key_press/trigger_keydown
s/_is_cell_editor_focused/is_cell_editor_focused
s/_is_cell_on/is_cell_on